Shedding New Light on Sunscreen

Roger I. Ceilley, MD, FAAD, FACMS, clinical professor of dermatology at the University of Iowa in Des Moines, detailed what people need to know about this crucial topic in his presentation on photoprotection at the 2022 Fall Clinical Dermatology Conference for PAs & NPs.¹

He set the stage for his indepth analysis by noting that sunlight is the major environmental risk factor for melanoma. Ceilley cited a study that showed between 89% and 95% of annual melanoma cases are caused by solar UV radiation exposure.² “The authors concluded that avoidance of UV radiation will reduce the incidence of malignant melanoma,” he said.

However, he noted that while UV radiation exposure without protection may be responsible for “the vast majority” of melanoma cases, it is not the only driver for this potentially deadly skin disease. As a 2021 study reported, “indoor tanning beds, immunosuppression, family history and rare congenital diseases, moles, and obesity [also] contribute to the disease”.³

Next, Ceilley presented evidence for the fact that sunscreen reduces melanoma risk. He specifically mentioned a study from Australia which followed 1,621 patients and found that melanoma risk was significantly lowered by regular sunscreen use.⁴ Another study was reviewed which concluded that sunscreen use likely reduced skin cancer incidence by 10-15% and that sunscreen should be a component of a comprehensive sun protection strategy.⁵ “Sunscreens are an important part of sun protection that includes avoiding the midday sun and wearing sun-protective clothing”, said Ceilley.

When it comes to SPF, the number on the package may not match up with the amount of sun protection provided in average patient populations due to inadequate or improper use. People often don’t apply the recommended amount of sunscreen, so Ceilley offered tips how to apply it effectively. Given that patients apply sunscreens at densities far less than that utilized to determine the SPF value listed on the product label, a real-world/actual usage study concluded that SPF 100+ sunscreen was significantly more effective than SPF 50+ sunscreen.⁴ Ceilley stressed that these results demonstrate that there is a need for sunscreen labelled with SPFs greater than 50+ to provide consumers with better choices for sunscreen products. In summary, he remarked, “higher SPF sunscreens have multiple clinical benefits to users.” He highlighted a specific study which demonstrated that an SPF 80 formulation proved more effective than an SPF 50 formulation in a single application model during a high UV test environment.⁶ When it comes to sunscreen protection beyond UV, “tinted sunscreens and those with antioxidants appear to be helpful in protecting against visible and infrared light damage to the skin,” Ceilley said.

Ceilley then touched upon absorption concerns with topical sunscreens. In the safety studies that were conducted, serum levels for risk were selected arbitrarily without scientific evidence and he reported that the theoretical risk of absorption has not been seen clinically, despite the fact that the tens of millions of people using sunscreen each summer weekend effectively constitute a large-scale experiment, in Ceilley’s view. Ceilley touched upon the most recent controversy specifically regarding oxybenzone in sunscreen as a cancer causing agent. He cited a 2018 study which reviewed oxybenzone and sunscreen and offered tips on counseling patients in a clinical setting on this controversial issue.⁷ Ceilley suggested that in discussion with patients, it is important to begin by emphasizing the data supports the fact that sunscreen use lowers skin cancer risk. He also advised informing patients that while laboratory evidence suggests oxybenzone may have negative environmental effects, the conditions in those experiments were not reflective of real-world conditions and thus are inconclusive. Patients may use inorganic sunscreens if they prefer, but should be informed about their disadvantages. For patients concerned about benzene toxicity, Ceilley cited research that shows that sunscreen users had lower levels of blood benzene than never-users, suggesting other factors may be a stronger influence than sunscreen.⁸ Ceilley also reminded healthcare practitioners that the best sunscreen choice is one patients will use consistently and that cost and cosmetic acceptability are also factors.

Ceilley ended his talk by reinforcing that photoprotection is an important topic for both providers and patients alike and that there are data to show that it lowers skin cancer risk. Unfortunately, there still represents a knowledge gap in the public perception of the benefits of sunscreen and its proper usage. The public needs better education on the benefits of high SPF levels, the safety of sunscreens and better understanding appropriate use of systemic photoprotection and skin supplements.

Disclosures:

Ceilley serves as a consultant for Biofrontera, Sun Pharma and Ferndale.

This article originally appeared on Dermatology Times.

References

1. Ceilley RI. What You Really Need to Know About Photoprotection. Presented at the 2022 Fall Clinical Conference for PAs & NPs, held June 3-5, 2022; Scottsdale, AZ.

2. Juzeniene A, Grigalavicius M, Baturaite Z, Moan J. Minimal and maximal incidence rates of skin cancer in Caucasians estimated by use of sigmoidal UV dose–incidence curves. International Journal of Hygiene and Environmental Health. 2014;217(8):839-844. doi:10.1016/j.ijheh.2014.06.002

3. Saginala K, Barsouk A, Aluru JS, Rawla P, Barsouk A. Epidemiology of Melanoma. Med Sci (Basel). 2021 Oct 20;9(4):63. doi: 10.3390/medsci9040063. PMID: 34698235; PMCID: PMC8544364.

4. Green AC, Williams GM, Logan V, Strutton GM. Reduced melanoma after regular sunscreen use: randomized trial follow-up. J Clin Oncol. 2011;29(3):257-263. doi:10.1200/JCO.2010.28.7078

5.Olsen CM, Wilson LF, Green AC, et al. Cancers in Australia attributable to exposure to solar ultraviolet radiation and prevented by regular sunscreen use. Aust N Z J Public Health. 2015;39(5):471-476. doi:10.1111/1753-6405.12470

6.Williams JD, Maitra P, Atillasoy E, Wu MM, Farberg AS, Rigel DS. SPF 100+ sunscreen is more protective against sunburn than SPF 50+ in actual use: Results of a randomized, double-blind, split-face, natural sunlight exposure clinical trial. Journal of the American Academy of Dermatology. 2018;78(5):902-910.e2. doi:10.1016/j.jaad.2017.12.062

7. Mirsky RS, Prado G, Svoboda RM, Rigel DS. Oxybenzone and Sunscreens: A Critical Review of the Evidence and a Plan for Discussion with Patients. J of Skin. 2018;2(5). doi:10.25251/2.5.0

8. Olsen CM, Wilson LF, Green AC, et al. Cancers in Australia attributable to exposure to solar ultraviolet radiation and prevented by regular sunscreen use. Aust N Z J Public Health. 2015;39(5):471-476. doi:10.1111/1753-6405.12470